1. The Field of the Invention
The present invention relates generally to orthopedic implants and associated methods, and more particularly, to facet joint replacement implants and methods.
2. The Relevant Technology
Many people experience back pain. Back pain is not only uncomfortable, but can be particularly debilitating. Many people who wish to participate in sports, manual labor, or even sedentary employment are unable to do so because of pains that arise from motion of or pressure on the spinal column. Such pains are often caused by traumatic, inflammatory, metabolic, synovial, neoplastic and degenerative disorders of the spine.
In order to alleviate such injuries and pains, spinal fusion techniques have been used for many years to essentially lock two vertebrae together. More recently, artificial discs have been used to replace natural intervertebral discs to correct disc pathologies, while still permitting the adjacent vertebrae to move with respect to each other. Various implants have also been proposed for the partial or complete replacement of vertebral facet joints to alleviate discomfort associated with diseased or atrophied articular processes, while still permitting intervertebral motion.
One deficiency in many of the proposed implants and methods is that they only permit the replacement of articular surfaces on a single vertebral level (i.e., a single “facet joint”). Many known devices are attached to a vertebra in such a manner that a similar device for an adjacent level cannot be attached to the same vertebra. Accordingly, facet joint pathologies that extend along multiple joints cannot effectively be corrected.
Another deficiency in many of the proposed implants and methods is that, once an implant has been used to replace part or all of a single facet joint, the implant interferes with the use of another implant to fuse an adjacent vertebral level. Accordingly, the correction of spinal pathologies extending along multiple vertebral joints is further inhibited.